1. Field of the Invention
The present invention relates to telephones. More specifically, the present invention relates to multiple handset cordless telephones operable within a wireless telephone network.
2. Description of the Related Art
Users of modem telephony services have a wide range of products and services available to them. Among these is the conventional wire-line telephone that provides access to the Public Switched Telephone Network (“PSTN”). The classic telephone-set includes a base and a handset. The two are connected together by a cord that carries duplex audio, and sometimes signaling information. The base is further connected to the PSTN with a twisted pair of wires running from the user's telephone location to a telephone company central office. The handset rests on a hook switch on top of a cradle on the base. Over the years, many more convenient features have been added to telephones and telephone services. Cordless telephones were developed, which eliminated the cord between the base unit and the handset, but did not eliminate the twisted pair of wires connecting the base to the central office. In a cordless telephone, the cord is replaced by a pair or radio transceivers, one in the base and one in the handset, that allow the user to move freely within the radio coverage range of the transceivers. Wireless telephone networks have also been developed and deployed. Wireless networks eliminate the need for interconnection of the telephone terminal unit to the PSTN by a twisted pair of wires. Rather, a network of fixed radio transceivers replaces the wire-line network. Each wireless telephone handset contains a radio transceiver that communicates wirelessly with the wireless network. Wireless telephone networks greatly expand the roaming ability of the users as compared with cordless telephones because the network allows roaming of terminal units between several fixed radio transceivers.
The advent of cordless and wireless telephone service, as well as the dramatic increase in other telephony services, has changed the way people use telephones and their expectations about the convenience of service. Multiple extension systems exist that allow intercom functions as well as shared telephone resource functions. Cordless telephone headsets offer hands-free roaming. Most homes and office have multiple telephone extensions with different types of telephone instruments selected to meet users' desires. Many users have both a wire-line telephone and a wireless telephone. Many homes and offices enjoy the convenience and freedom of movement afforded by cordless telephone service. There is an expectation by users today that telephone service is ubiquitous and that people can be reached virtually anywhere and at anytime.
While there has been a great increase in the range of products and services available to users of telephony services, the increase has not been without some problems and costs. Many users now have wireless telephone number as well as a wire-line telephone numbers. This can lead to confusion and wasted time in attempts to reach a user when their whereabouts is not known. It is also more expensive to maintain two separate types of telephone service. Many of the convenient services offered by home or office telephone systems are not available with a wireless telephone. For example, multiple extensions, speakerphones, cordless telephone features, and system growth flexibility. Wireless and cordless services do create some user confusion as well. Some users prefer the classic desk type telephone, the so-called “2500 set”, as opposed to the more technical user interface that wireless telephones employ. Others prefer advanced telephone instruments, such as cordless headsets or designer products. There are also issues as to battery charging and battery life. Tiny wireless telephones do not lend themselves to large capacity storage batteries that enable extended periods of battery-only operation. Thus, there is a need in the art for a system and method to integrate wireless telephony with conventional wire-line types of features and services while still maintaining the portability and ubiquitous nature of telephony service the users have come to expect.